1991 Volume 40 Issue 449 Pages 199-204
To investigate the time and temperature dependences of the fatigue behavior of carbon/aramid hybrid unidirectional FRP laminates (C/A hybrid FRP) in which CFRP layer was sandwiched between two AFRP layers, three point bending fatigue tests for CFRP, AFRP and C/A hybrid FRP were conducted at several levels of temperature and frequency. The flexural fatigue strengths of CFRP, AFRP and C/A hybrid FRP depended on temperature and frequency, and the reciprocation law between time and temperature held for these strengths. The flexural fatigue fracture of C/A hybrid FRP was classified into two modes by temperature, frequency and number of cycles to failure Nf. One is triggered by the tensile fracture of AFRP layer in the range of low temperature, high frequency and low Nf where the fatigue strength changes scarcely with temperature, frequency and Nf. The other is triggered by the compressive fracture of CFRP layer in the range of high temperature, low frequency and high Nf where the fatigue strength decreases remarkably with temperature, frequency and Nf.
